1. Field of the Invention
This invention is in the field of attachment systems for composite panels and the like.
2. Description of Related Art
The exterior walls of a building, or any other building-like structure, may be made of concrete block or other exterior finishes. Those walls, however, are generally unattractive, and may not be water tight and weather resistant. Consequently, the architect or builder will choose to cover them with an attractive, weather-resistant siding. Alternatively, the building may be composed of stud-formed walls, the interior of which are finished with sheetrock or the like, and the exterior of which are unfinished so that the studs are exposed. In this case, the builder needs to attach an exterior siding to the studs to finish the walls. Likewise, worn exterior walls of new or old buildings may be finished or refaced with a new siding.
One such exterior wall siding that is used by builders and architects is a composite panel. Composite panels provide the building with an attractive finish, improved weather resistance and water tightness, and increased insulation value when used in conjunction with insulation. They also bend, and are thus well-suited for covering curved walls. A composite panel is generally formed of two or more materials. For example, an Alpolic.RTM. or Alucobond.RTM. composite panel is made of a thin aluminum skin, having a thickness of between twenty to thirty thousandths of an inch, that is bonded to both sides of a thermoplastic core, for a total of thickness of 3-6 mm. Composite panels are typically rectangular, and can be manufactured to the desired length and width to suit the overall design. For example, a typical panel is about 4 feet in width and 8 feet in length. Of course, other shapes and dimensions are possible. Additionally, the panels may be used on interior wall structures.
Various components and systems are currently known and used for attaching composite panels to exterior building walls. In one such known system, called a "glazed in system", the panels are attached to the building as would be a pane of glass. A cross-section view of a horizontal joint of this system, is shown in FIG. 1. A female extrusion bracket 100 is fastened to the sub girt 101 of the wall or stud 107 with a fastener 106, with a leveling shim 102 therebetween. A male extrusion bracket 103 holds composite panels 105a and 105b against the female extrusion bracket 100, after gaskets 104 have been installed between the extrusion brackets 100 and 103 and the panels 105a and 105b.
A cross-section view of another system, typically called an edge-grip system, is shown in FIG. 2. In this system, an I-shaped extrusion bracket 120, comprising a vertical spine 120a, a top horizontal gutter 120b and a bottom horizontal gutter 120c, is fastened through shims 126 to a sub girt 121. Side rails 122 and 123 are respectively attached, using structural adhesive tape 128 and structural silicone 129, to the edges of the composite panels 124a and 124b, which have been machined in tongue-and-groove fashion to receive the side rails. Side rails 122 and 123 are inserted between the top and bottom horizontal gutters 120b and 120c of the I-shaped extrusion bracket 120. Gaskets 125 are positioned between the gutters 120b and 120c and the side rails 122 and 123 to provide a water tight seal. Upon installation, the panels are about 1/2 inch apart at the joint and 23/8 inches away from the wall.
Another type of panel attachment system is called a "route-and-return system". FIG. 3 shows in cross-section, an edge-grip route-and- return system, which uses an extruded channel 130. A female portion 131 of the channel 130 has a composite panel 132 riveted thereto. The end of the panel 132 consists of two edges 132a and 132b, the first edge 132a being perpendicular to the face 132c of the panel, and the second edge 132b being perpendicular to the first edge 132a. The second edge 132b is inserted into and riveted with rivet 134, at the factory, to the female portion 131. The channel 130 and panel 132 attached thereto are positioned and screwed to the sub girt 135, on site, using screw 133. A second panel 136 has an edge 136a, perpendicular to the face 136b of the second panel, which is factory riveted to a female extrusion bracket 137. The female extrusion bracket 137 is hooked over a male portion 138 of the channel 130.
The above attachment systems have numerous disadvantages. First, they all require complicated, lengthy and costly ways of attaching the panels to the extrusion brackets and ultimately to the exterior walls. Further, in certain systems, some of the attachment work must be first performed at the factory, which reduces the flexibility of later on-site installation. The following route-and-return systems simplify the attachment of the composite panels to the extrusion brackets, and are thus less costly, quicker and more flexible.
For example, FIG. 4 shows a cross-section view of a route-and-return system, and in particular a vertical joint in this system. In this vertical joint, a metal clip 140 is fastened with fasteners 141 to the sub girt 142 of the exterior wall 143. To permit leveling adjustments to be made to the panel, the metal clip 140 is shimmed to the wall by placing a shim 144 between the metal clip 140 and the sub girt 142. The metal clip 140 is substantially I-shaped in cross-section, and runs at least the length of the composite panels 145a and 145b (or at least the width for horizontal joints). The larger flange of the "I" attaches to the sub girt 142, while the smaller flange of the "I" engages the attachment system extrusion brackets 146a and 146b. Each composite panel is routed to form an approximate 1/8 inch depth groove 147, although in general groove depth may vary depending on the panel thickness. Those grooves are formed, for example, an inch or two away from the side edges of the panel. Thus, each panel has four grooves. The corner pieces of the panel, at which the grooves intersect, are removed. This allows the panel edges 148a and 148b to be turned down around the groove 147 and away from the main panel portions 145a and 145b, respectively, to form down-turned edges. Bracket 146a is fastened to the down-turned edge 148a of the panel, and bracket 146b to the down-turned edge 148b, by screws or other fasteners 149. Each bracket is held against the metal clip 140 by pressure from the other three attached sides of the panel. The installation is completed by adding a standard backing rod 150, which is positioned between the down-turned edges 148a and 148b and over the smaller flange metal clip 140. The backing rod 150 is made of polyvinyl or other plastic and backs up the flexible water-resistant sealant 151 applied thereon.
A cross-section view of a horizontal joint of another route-and-return system is shown in FIG. 5. This system uses male and female extrusion brackets, 161 and 160, to attach respectively first and second composite panels, 162 and 163, to a wall 164. The female extrusion bracket 161 is screwed to the wall 164 through shims 165. A one-inch down-turned edge 162a of the first composite panel 162 is screwed to the female extrusion bracket 161 with screw 166. Similarly, a down-turned edge 163a of the second composite panel 160 is screwed to the male extrusion bracket 160. The male extrusion bracket 160 is inserted into, and held in place by, the female extrusion bracket 161. The panels attachment is completed by inserting a standard backer rod 168 between the down-turned edges 162a and 163a of the composite panels 162 and 163, and applying a flexible sealant 169 thereon. Upon installation, the panels are approximately 21/4 inches from the wall, and approximately 1/2 inch apart at the joint.
Another route and return panel attachment system is shown in FIGS. 6A-6D. FIG. 6A depicts a cross-section of a horizontal joint, in which a female extrusion bracket 170 is screwed to the wall 172 using screw 173, with shims 171 therebetween. The down-turned edge 174a of a first panel 174 is riveted, using pop-rivet 176, to a first male extrusion bracket 175, while the down-turned edge 177a of a second panel 177 is riveted to a second male extrusion bracket 178. The male extrusion brackets 175 and 178 are each hooked over portions 170a and 170b, respectively, of the female bracket 170. FIG. 6B shows a vertical joint, in which extrusion brackets 181 and 182 are respectively riveted to the down-turned edges 174b and 177b of panels 174 and 177. Extrusion brackets 181 and 182 are held against the wall by bracket 183, which is screwed to the wall 172 through shims 184. FIGS. 6C and 6D respectively show single-panel horizontal head and vertical jamb joints. The horizontal head joint uses a single male extrusion bracket 190 to hold a single panel 191 via edge 191a riveted thereto. The male extrusion bracket 190 is hooked into a female extrusion bracket 192 which has already been attached to the wall 172 through shims 193. In the vertical jamb joint, a down-turned edge 197a of a single panel 197 is riveted to a male extrusion bracket 198. The male extrusion bracket hooks into a female extrusion bracket 199 which has been screwed to the wall 172. In these joints, a standard vinyl backer rod 179 and flexible sealant 180 may be used to fill the 5/8 inch gap between the panel edges (FIGS. 6A and 6B), between the panel edge and coping 195 (FIG. 6C) or between the panel and jamb 196 (FIG. 6D).
The above-described route-and-return systems, however, all require fastening the panels to the extrusion brackets with screws or rivets. This is a lengthy process which adds to the cost of the installation.
Another route-and-return system, marketed as the "Universe.RTM. System, is shown in FIGS. 7A and 7B. This system attempts to solve the above problems by using a screwless attachment device. FIG. 7A is a cross-section view of this system. The attachment device 200 runs the length of the panel and is attached by screw 209 through one or more plastic shims 201 to a wall or stud 202. Device 200 has two rails with rounded, inward-facing ends 200a. The composite panels 204 and 205 have, in addition to the routed grooves 203 around which the edges 204a and 205a are turned down, a routed groove 206 on the down-turned edge itself. The rounded ends 200a of the attachment device 200 are inserted into the panel edges 204a and 205a. Thus, the panels are held in place by the rounded ends of the rails rather than screws or rivets. A vinyl backer rod 207 is inserted between the down-turned edges 204a and 205a, upon which sealant 208 is applied. A perspective view of the same system is shown in FIG. 7B.
The prior attachment system requires, however, extra grooves to be routed in the down-turned edges of the panels to engage with the rounded ends of the rails. Moreover, the rounded rails do not completely or positively interlock with the panels.